A wellbore 10 in FIG. 1A has casing 12/16 disposed in the wellbore 10 and held in pace by cement 15. The casing 12/16 extends from a wellhead 20, which has valve elements 22 to control the flow of fluid from the wellbore 10 as schematically shown. Downhole, the inner casing 12 has a downhole deployment valve (DDV) tool 30 that operates as a check valve separating uphole and downhole portions 14u-d of the casing 12 when closed.
Disposed on the casing 12, the DDV tool 30 can have a housing 32, a flapper 34 with a hinge 36 at one end, and a valve seat 35 in an inner diameter of the housing 32 adjacent the flapper 34. Alternatively, the flapper 34 may be replaced by a ball valve (not shown) or some other mechanism. A more detailed discussion of a DDV tool can be found in U.S. Pat. No. 7,350,590, which is incorporated herein by reference.
Typically, the DDV tool 30 threads to the casing 12 so the DDV tool 30 forms part of the casing string. This allows the DDV tool 30 to be run into the wellbore 10 along with the casing 12 prior to cementing operations. Alternatively, the DDV tool 30 can be run with a liner hanger and a tieback assembly or some other technique.
Once installed downhole, the DDV tool 30 acts as a one-way valve and can be remotely operated through an armored control line 44 that runs from the DDV tool 30 to the surface. Clamps (not shown) typically hold the control line 44 to the casing 12 at regular intervals for protection, and the control line 44 cements in the cemented area around the casing 12.
At the surface, a rig control system 40 communicates with the DDV tool 30 via the control line 44 and operates the DDV tool 30 by remotely opening and closing the flapper 34 from the surface of the well. Typically, the control system 40 uses the control line 44 to carry hydraulic fluid or electrical current to an actuator 38 on the DDV tool 30. Once actuated, the flapper 34 can open or close the bore through the tool 30.
When closed, the DDV tool 30 isolates the uphole portion 14u of the casing 12 from the downhole portion 14d so any pressure remaining in the uphole portion 14u can be bled out through the valve assembly 22 at the surface. With the uphole portion 16u of the wellbore free of pressure, the wellhead 20 can be opened so operators can perform various operations, such as inserting or removing a string of tools. Downhole, the DDV tool 30 allows a downhole assembly 25 on drillpipe to pass through the DDV tool 30 when opened. When the drilling assembly 25 trips out of the well, the DDV tool 30 can close and seal off the downhole fluids again.
To connect the control system 40 to the DDV tool 30, hydraulic fluid or power has to pass through the wellhead 20. As noted previously, the DDV tool 30 is run downhole disposed on the casing 12 with the control line 44 running along the casing 12. At the surface, a casing hanger (not shown) installs on the proximate end of the casing 12, and the control line 44 runs from the hanger down to the DDV tool 30. The DDV tool 30, control line 44, casing 12, and casing hanger lower into the wellhead 20 until the casing hanger lands on an internal shoulder of the wellhead 20. Once landed, ports in the wellhead 20 and casing hanger allow hydraulic fluid or power from the control system 40 to pass through the wellhead 20, to the control line 44, and down to the DDV tool 30.
As an example, FIG. 1B shows a casing hanger 50 for supporting a control line 44 of a DDV tool 30 in a wellhead as disclosed in US2008/0121400. The hanger 50 includes a passageway 51 through which hydraulic fluid can flow through the hanger 50 between the control system's hydraulic line 42 at the head 24 and the hydraulic control line 44 extending down to the DDV tool 30. The passageway 51 provides a conduit to a side of the hanger 50. The passageway 51 can extend in a different direction to create a second passageway 53 in the side of the hanger 50. A hydraulic tool port 52 formed on the passageway 51 couples to the hydraulic line 44.
At the wellhead 20, a hydraulic side port 54 is formed at the exit of passageway 53 in the side. An access opening 26 to the hydraulic side port 54 is formed to the side of the head 24 and aligned with the hydraulic side port 54 on the hanger 50 when the hanger 50 is seated in the head 24. The side port 54 can be disposed in a skirt of the hanger 50, where the skirt is generally a reduced concentric portion of the hanger 50. The skirt is situated below a shoulder 58 of the hanger 50 where the shoulder 58 is sized to engage a corresponding landing 28 on the head 24.
Although the arrangement of FIG. 1B may be effective, operators may need to install a casing hanger in an emergency operation to support the casing if problems occur during installation of casing having a DDV tool. For example, the casing may become stuck when being run downhole, and operators may need to install an emergency casing hanger on the DDV casing head of the wellhead.
Typically, operators use a slip hanger to support the casing in such an emergency operation. However, a typical slip hanger lacks features that allow control lines to pass in effective way. In the past, operators have used through holes in the slip hanger to pass the control lines. Unfortunately, handling the control lines and slip hanger in an emergency operation can be difficult, and the control line can rupture due to tension applied when moving the casing and installing the slip hanger.
The subject matter of the present disclosure is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.